1. Field of the Invention
This invention pertains generally to pressure switches, and more particularly to fabrication of a micromechanical digital pressure switch array from align fusion bonded silicon wafers.
2. Description of the Background Art
Mechanical pressure switches and their fabrication are well known in the art. Such devices typically provide an output signal in the form of a switch closure or the like in response to application of mechanical or atmospheric pressure. Current fabrication techniques for conventional pressure switches, however, result in pressure switches which are bulky and which do not provide accurate digital output for multiple pressure thresholds.
Several types of micromachined pressure switches can also be found. For example, Terry et al., A Monolithic Silicon Switch System for Tire Pressure Measurement, published in Transducers '87 Technical Digest p. 76 (1987) discloses a silicon micromachined pressure switch with electrostatic hysteresis for tire pressure monitoring. Huff et al., A Threshold Pressure Switch Utilizing Plastic Deformation of Silicon, published in Transducers '91 Technical Digest p. 181 (1991) discloses a threshold pressure switch utilizing plastic deformation of a silicon membrane using wafer bonding technology.
The foregoing information reflects the state of the art of which the applicant is aware and is tendered with the view toward discharging applicant's acknowledged duty of candor in disclosing information which may be pertinent in the examination of this application. It is respectfully stipulated, however, that none of these disclosures teach or render obvious, singly or when considered in combination, applicant's claimed invention.